Process of making underground structures for underdraining and shielding purposes

ABSTRACT

A trench dam is made by an apparatus which digs a trench in a water-permeable ground layer, then lays a perforated drainage conduit in this trench, partially fills the trench over the conduit with gravel to form a porous gravel bed, and then fills the trench over the bed with a mixture of the excavated earth and a binder to form a waterproof wall. This operation is carried out under a silt-water suspension to prevent collapse of the trench walls which are undercut by milling wheels on the lower end of the cutter. Clear water is pumped into the conduit during these operations to drive off this silt-water suspension.

United States Patent [72] lnventor BOMIII Zakiewicz Cracow, Poland [21] Appl. No. 791,358

[22] Filed Jan. 15, 1969 [45] Patented Sept. 7, 1971 [73] Assignee Przedslebiorstwo Specjalistyczne Gornictwa Surowcow Chemicznych Krakow, Poland [32] Priority Jan. 22, 1968 [3 3 Poland [54] PROCESS OF MAKING UNDERGROUND STRUCTURES FOR UNDERDRAINING AND 72.5, 72,l, 72.2, 35, ll, l3;37/60 [56] References Cited Primary Examiner lacob Shapiro Att0mey-l(arl F. Ross ABSTRACT: A trench dam is made by an apparatus which digs a trench in a water-permeable ground layer, then lays a perforated drainage conduit in this trench, partially fills the trench over the conduit with gravel to form a porous gravel bed, and then fills the trench over the bed with a mixture of the excavated earth and a binder to form a waterproof wall. This operation is carried out under a silt-water suspension to prevent collapse of the trench walls which are undercut by milling wheels on the lower end of the cutter. Clear water is pumped into the conduit during these operations to drive off this silt'water suspension.

PATENTED SE? 719?: 3,603,097

Bohdan Zakiewicz INVENTOR.

ATTORNEY PROCESS OF MAKING UNDERGROUND STRUCTURES FOR UNDERDRAlNING AND SIIIELDING PURPOSES The invention comprises a process of making underground structures for underdraining and shielding purposes and a device therefor. The underground structures known in the art, particularly waterproof shields or trench dams made in permeable ground layers, effectively protect the shielded ground or objects against groundwater inflow as long as their bottom parts are embedded or immersed in impermeable ground layers. If, however, impermeable ground layers appear only at great depth, making a deep dam with its bottom part immersed in the impermeable ground layer proves to be a very difficult technical task which is unprofitable from an economical point of view.

Hence, in this case it is necessary to build a shallow shielding or dam entirely placed in the permeable layer and having a drainage collector built in to its base.

Placing the drainage collector in the bottom part or base of the shielding as well as draining bottom water from the ground by means of the collector conduit enables the water level to be lowered below the ground surface and allows the protected grounds to be protected against underflooding with water infiltrating from natural and/or artificial water reservoirs, in particular in seasons when the water level is especially high.

The structure for draining and shielding effectively prevent the natural underdrainage of a riverbed which is of outstanding value in protection of river waters against inflow of ground waters polluted with chemicals.

The known techniques of making underground drainageshield structures comprise the steps of laying a drainage collector by means of a sliding device in a narrow cut previously excavated in a known manner and subsequently filling the part of the out which is above of the drainage collector with a waterproof material. These operations are performed behind, in the directions of advance, a device which excavates the narrow cut.

Those techniques are, however, very disadvantageous considering both the complicated operations to be performed as well as the necessity of using separate devices for excavating the narrow cut for placing the drainage collector and for building a waterproof wall. The invention is aimed at simplifying the technique of making a drainage-shield structure, increasing its usefulness, and reducing the costs of its manufacture. These technical problems are solved according to the invention by building a drainage collector in the bottom of a narrow cut or trench and filling the cut above the collector with a waterproof material simultaneously while advancing a cutting-milling machine through the ground to excavate the trench.

The process and the device according to the invention are shown in the enclosed drawing wherein:

FIG. 1 is a diagrammatic longitudinal section through the apparatus according to the invention; and

FIG. 2 is a view taken in the direction of arrow II of FIG. 1.

The apparatus comprises a cutting machine 1 having a frame 1' furnished with sliding runners 2 for placing a perforated drainage collector conduit 3 and with a dispenser chute 4 to heap a gravel-sand bed on top of this conduit 3.

The shaft 5' of the adjustable sprocket 5 is coupled with additional milling wheels 6 positioned outwardly from the carrying frame 1 of the cutting machine. By means of these milling wheels 6 clay formed from the silt-water suspension on the walls of the cut C is removed and also the bottom part of the cutting C intended to receive the drainage collector 3 is enlarged.

Also mounted on the cutter frame 1 of the cutting-milling device 1 is a pump tube 7 provided with inlet ports 7 for receiving excavated earth, a pneumatic lifting jack 8 and aerating means 9 being provided.

The ground excavated by means of the cutter chain 1" is pumped out by the (5mm tube 7 to a trough l0 whence it is transported back an lai again in the excavation by means of a dispenser chute 11 and a dumping hopper 12 according to the direction shown by arrows 13.

In the course oflaying the drainage collector conduit 3 and a gravel-sand bed and excavated ground, which latter can be mixed with packing materials in the section 15, pure water is continuously pressed into the drainage collector 3 according to arrow 16 in order to withdraw eventual remainders of silt suspension from the drainage section of the cut and to wash out the drainage collector 3 and the porous gravel-sand bed 14.

The drainage section 17 is cut by means of the milling wheels 6. During the action of the cutting chain 1" according to the arrows shown in FIG. 1, the device which is traveling in the direction shown by arrow 18 along the line of an already made trench 19 trenches the ground 20 and simultaneously lays the drainage collector 3 and a gravel-sand bed 14 in the cut to make a waterproof wall in the section 15 positioned above the gravel-sand bed 14.

There is shown at 21 a rolling platform supporting the cutter l and a drive and transmission 22.

Claim 1. A method of making a trench dam comprising the steps of:

forming a trench in a water-permeable ground layer below a silt-water suspension;

laying a perforated drainage conduit directly on the base of said trench;

partiallyfilling said trench with gravel to form a porous gravel bed therein above said conduit;

forming a waterproof wall in said trench above said bed; and

forcing substantially clear water through said conduit during and after laying thereof to drive off said silt-water suspension.

2. A method of making a trench dam comprising the steps of:

forming a trench in a water-permeable ground layer;

laying a perforated drainage conduit directly on the base of said trench;

partially filling said trench with gravel to form a porous gravel bed therein above said conduit;

forming a waterproof wall in said trench above said bed; and

mixing the earth removed to form said trench with a binder, said wall being formed with the mixture of earth and said binder.

3. A method of making a trench darn comprising the steps of:

forming a trench in a water-permeable ground layer;

laying a perforated drainage conduit directly'on the base of said trench;

partially filling said trench with gravel to form a porous gravel bed therein above said conduit;

forming a waterproof wall in said trench above said bed;

and, all of said steps are carried out substantially simultaneously and jointly, said method further comprising the step of pumping water from said conduit upon the formation of said waterproof wall. 

1. A method of making a trench dam comprising the steps of: forming a trench in a water-permeable ground layer below a siltwater suspension; laying a perforated drainage conduit directly on the base of said trench; partially filling said trench with gravel to form a porous gravel bed therein above said conduit; forming a waterproof wall in said trench above said bed; and forcing substantially clear water through said conduit during and after laying thereof to drive off said silt-water suspension.
 2. A method of making a trench dam comprising the steps of: forming a trench in a water-permeable ground layer; laying a perforated drainage conduit directly on the base of said trench; partially filling said trench with gravel to form a porous gravel bed therein above said conduit; forming a waterproof wall in said trench above said bed; and mixing the earth removed to form said trench with a binder, said wall being formed with the mixture of earth and said binder.
 3. A method of making a trench dam comprising the steps of: forming a trench in a water-permeable ground layer; laying a perforated drainage conduit directly on the base of said trench; partially filling said trench with gravel to form a porous gravel bed therein above said conduit; forming a waterproof wall in said trench above said bed; and, all of said steps are carried out substantially simultaneously and jointly, said method further comprising the step of pumping water From said conduit upon the formation of said waterproof wall. 